| 摘要 |
PURPOSE:To attain the continuous test of a data transmission link despite hit of a carrier wave occurs by deciding a defective decision result for the output of a deciding circuit during the hit of carrier wave and resetting the deciding circuit to its original state when the hit is recovered and at the same time adding a carrier wave break countermeasure circuit to a deciding pseudo random pattern generating circuit. CONSTITUTION:When hit of a carrier wave break arises at a data transmission link 1, a carrier wave break countermeasure circuit 9 detects a carrier wave break detection signal 10 and decides a defective decision result for the output of a deciding circuit 7. Thus an error counter circuit 8 can count the bits. When the hit of carrier wave is recovered, the circuit 7 is reset to its original state. At the same time, a reception circuit 5 sets a pseudo random pattern to a deciding pseude random pattern generating circuit 6 after the hit of carrier wave is recovered and for a period during which the next pattern is received after a 9-bit data pattern is received first. In other words, the test of the link 1 is continued even after the recovery of the hit of carrier wave by synchronizing the circuit 6 with a pseudo random pattern generating circuit 4. |
